Lubricating grease composition



Patented Mar. 13, 1951 2,545,114 V LUBRICATING GREASE COMPOSITION Herschel G. Smith, Wallingford, and Troy L. Cantrell, Lansdowne, Pa., assignors to Gulf Oil Corporation, Pittsburgh, Pa., a corporation of Pennsylvania No Drawing. Application July 30, 1948, Serial No. 41,706

This invention relates to lubricatin grease compositions, and more particularly, to grease compositions which find advantageous applications in the lubrication of light mechanisms, such as small motors, air motors and the like, exemplified by the type of motor used to operate windshield wipers.

9 Claims. (Cl. 25240.7)

In general, when such motors as referred to hereinabove have been operated without a change of lubricant over a prolonged period, the lubricating composition becomes oxidized, re-

sulting in the formation of gummy substances, --l

The tendency of a mineral lubricating oil base to separate or bleed from a grease composition in which the oil has been compounded is well known in the art. Excessive bleeding will tend to result in a complete break-down of the grease involved, to the detriment of any mechanism lubricated thereby.

Accordingly, it is an object of this invention to provide improved lubricating grease compositions characterized by their resistance to oxidation.

A further object of this invention is the provision of improved lubricating grease compositions having suitable fluid consistency to be used in the operation of small motors without undue energy loss, and of such a nature that a single application of the lubricant will be sufficient for the life of the motor.

A still further object of this invention is the provision of stable lubricating grease compositions of improved homogeneity, such that the tendency for the separation of oil from the grease, i. e. fbleeding is substantially reduced.

Other objects will be apparent from the following description.

These objects are accomplished by the present I invention wherein we provide improved grease compositions comprising a mineral lubricating oil thickened to the consistency of a grease by a soap, and a metallo compound obtained by re.- acting an aqueous'slurry of a metal hydroxide selected from the group consisting of barium, strontium, magnesium'and calcium hydroxides with formaldehyde at a mildly elevated tempera:- ture and condensin the resulting product with aniline and a mono-alkyl phenol having from 4 to 12 carbon atoms in the alkyl substituent, said metallo compound being present in an amount sufficient to stabilize the grease against oxidative deterioration.

The metallo compound, which is added to a grease in accordance with our invention, is described and claimed in the copending application of Smith, Cantrell and Peters, Serial No. 790,440, filed December 8, 1947. As shown therein, the metallo compound is prepared by first reacting an aqueous slurry of the metal hydroxide and formaldehyde at a mildly elevated temperature, say F., but not exceeding 200 F. The exact nature of this reaction product is unknown, but the reaction product contains combined therein the metal of the metal hydroxides. This product is then condensed with completed, the temperature is raised to distill off all water, both that formed in the condensation and added with the ractants. The reactants are preferably employed in the proportions of 1 mol of metal hydroxide, 2 to 4 mols of formaldehyde, 0.5 to 1.0 mol of aniline and 2 to 4 mols of the mono-alkyl phenol.

The mono-alkyl phenols used in preparing the metallo compound have from 4 to 12 carbonatoms in thealkyl substituent. Thus, the alkyl substituent may include normal or branched chain butyl, amyl, hexyl, heptyl, octyl, decyl and dodecyl radicals. A preferred alkyl substituent is the tetramethylbutyl radical. The mono-alkyl phenols are preferably obtained by alkylating in known manner, in the presence of concentrated sulfuric acid, phenol with olefins having from 4 to 12 carbon atoms. Olefins, such as butene-l, isobutylene, the amylenes, di-isobutylene and tri-isobutylene may conveniently be employed. It is preferred to conduct the alkylation with di-isobutylene since the resulting product is primarily para tetramethylbutyl phenol.

In view of the multiple points of the respective molecules at which the reactants may react, it

is believed that a mixture of compounds is obtained. The designation of the reaction product as a metallo compound is intended to cover all the compounds present therein.

The following example illustrates a preparation of the metallo compound used in our greases.

EXAMPLE I Into a jacketed iron reaction vessel (No. 1) were charged 12.9 parts by weight of phenol and 16.5 parts by weight of di-isobutyiene. The vessel was closed and the mixture agitated. Then 0.6 part by weight of 94-98% sulfuric acid was added. Cold water was run through the jacket of the reaction vessel in order to maintain a reaction temperature below 220 F. When all of the materials had been added, the temperature was permitted to attain 220 F. and held at that temperature for four hours. The resulting para tetramethylbutyl phenol was dissolved in 73 parts by weight of a mineral lubricating oil.

Into an enamel lined reaction vessel (No. 2) were charged 4.6 parts by weight of calcium hydroxide with sufiicient water to make a slurry, to which was added 14.9 parts by weight of a 37% by weight aqueous solution of formaldehyde. The reactants were heated to a temperature of 160' F. for two hours. product of the calcium hydroxide and formaldehyde was added to the mineral oil solution of para tetramethylbutyl phenol in reactor vessel No. 1 with agitation for 15 minutes. Then 4.3

cobalt, nickel, cadmium, mercury, etc.

ency of a grease by a suitable soap. These greases themselves are well known in the art and may be manufactured by conventional methods. For example, the mineral lubricating oil bases may include parafinic, naphthcnic and mixed base mineral lubricating oils, representative examples of which are shown in the following table. As known in the art, the soaps used in thickening the mineral oil base to a grease are fatty acid soaps derived from fatty materials such as tallow, lard, cottonseed oil, stearic acid, soy bean fatty acids and various other fats and fatty acids. The metal of the soap may be an alkali metal, an alkaline earth metal, and various other metals such as lead, zinc, chromium, tin, aluminum, iron, As will be understood by those skilled in the art, the soap and mineral oil base will be selected in accordance with the specific properties of the grease it is desired to manufacture. For the soft greases (semi-fluid oils) disclosed herein, it is preferred to employ the calcium soaps of fatty materials such as tallow, soy bean fatty acids, tallow-soy bean fatty acid mixtures, lard, cottonseed oil, and cottonseed oil-degras mixtures.

In acordance with our invention, small proportions of the hereindescribed metallo compound in a grease will substantially reduce the oxidative deterioration of the grease, as well as reduce any bleeding tendency. The amount of metallo compound used is sufficient to stabilize the grease against oxidative deterioration, and in general, small amounts, from 0.1 to 5.0 per cent by weight on the grease, will sufiice' The metallo compound may be dispersed in an already formed grease by simple mixing; or it may be introduced during the manufacture of the grease, for example by dissolving it in the mineral lubricating oil base used in the manufacture of the grease.

7 Considerable success has been obtained with the greases described as applied to the lubrication of small air and electric tvne motors, such as those used to operate windshield wipers and the like. It has been found that lubricating grease compositions prepared in accordance with this invention and used in such motors remain Thereafter, the reaction parts by weight of aniline were added and the temperature maintained below 200 F. The condensation product was then dried by increasing the temperature to 280 F., distilling ofi the water, following which the product was filtered. The additive thus prepared had the following properties:

Gravity, API ....r- 6-0-- 20.3 Viscosity, SUV, 210 F ..--a..'. 111.4 Color, NPA -1 4.75 Neutralization No. 0.92 alk. Ash as sulfate, per cent 4.513

stable over an extremely lon period of time; in fact, a sin le application of the grease is sufiicient for the life of the motor, yet the mechanisms receive sufficient lubrication to prevent undue wear. In such applications, the lubricating grease should be rather light, advantageously approaching what may be termed a semi-fluid oil. The rheological properties of such semi-fluid oils may be specified by the Com/is Test, Method 294 Gulf, which is set forth in detail in the copending application of Smith, Serial No. 644,369, filed January 30, 1946 now Patent No. 2,526,832,

i and entitled Apparatus for Measuring the Pressure Flow Characteristics of Greases. Briefly stated, the Convis Test reports the time in seconds required for 10 cc. of a grease sample to flow out of a Saybolt Furol vi cosimeter tube at a specified temperature, say 77 F., and under a force applied to the grease by a specified weight used to depress a piston which causes the grease to flow. Advantageous semi-fluid oils or soft greases exhibiting a Convis Test of from to 275 seconds at a temperature of 77 F. and a weight on the piston of 300 grams have been prepared and found particularly useful in light mechanisms as described hereinabove. However, this invention is not limited to semi-fluid oils, since a wide variety of grease compositions hav- Convis Test 5-11). pressure drop in8 the present invention may be compounded from 5 a variety of lubricating oil base stocks? The table below is illustrative of mineral lubricating oils which may advantageously be used asa base for the greases referred to, and sets forth the Example I exhibit a marked superiority against oxidative deterioration over the unimproved composition. The bleeding test indicates that the semi-fluid oil containing this metallo compound was in a more homogeneous statesince it exhibited less tendency for the separation of oil from the soap gel.

As stated hereinabove', our invention is not.

confined to semi-fluid oils but includes a wide inspection data of such 011$. variety of other greases of greater consistency.

Table 200 M. 0. v1300 Vis. 100/2 150M 0 500/3 1900/5 Base Oil Stock Inspection Texas Parafline Texas Texas Oil 0' Oil Oil Gravity, 0 API 22.9 21. 0 25:4 21 4 21.5 Viscosity. SUV:

100 F 21 305 102.2 2,.607 510 1,950 210 F 47. 9 38. 8 156 53. 9 97 Viscosity Index. "Z0 62 97 39 sh, 0C, F 415 365 V 355 585 385 475 Fire, 0C, F- 475 405 I 410 650 440 555 our, F +15," +10 +5 l0 +5 Color, NPA 2.0,, 4. 75 1. 75 4. 75 3. 0 4. 75 Carbon Residue Per Cent 0.02 0.08 0.01 1. 10 0.09 0.27 Neutralization No 0:02 0.02 0.06 0.05 0.05 0.03

-T'In the following examples, there are shown representative grease compositions prepared in accordance with our invention. Examples II and 'IlI'are representative of the excellent soft greases useful for lubricating windshield wiper mechahisms.

EXAMPLE II Senii-I improved Fluid Semi- Qil Fluid Oil Make-up, Per Cent by Weight, Lubricating Grease:

300 Vis. Texas Oil 91. 3 Calcium Soap oi Tallow- 6. 9 Glycerine 0. 7 Water 0.6 Compound of Example I 0. 5

In the above example, the grease wasprepared in the conventional manner, and the metallo compound dispersed in the grease so prepared.

EXAMPLE III Improved Semi- Semi-Fluid 011 Fluid Make-up. Per Cent by Weight:

300 Vis. Texas Oil 91 galcium Soap oi Tallow--- Method 294, Gulf 10cc. 77

F., 300 Grams Col Y 260. 1t. bluish red. +160. 0.67.

alkaline.

- AN-G-Sa Mod Per Cent by Weight fluid about 19. Oxidation Test, ASTM D 1 942-471, 210 F., 100 Hr.,

Pressure Drop, Lb. unstable 29.

hr. lb/pressure dro in 24 hr. p

In the above example, the metallo compound was first dissolved in the base oilf'and the base oil then compounded into a grease in con ventional manner. i

I The oxidation test shows beyond' doubt that the compositions containingthereactionproduct ot Examples IV, V and VI below are illustrative of such other grease compositions. Such examples demonstrate the stability against oxidative deterioration and-bleedingof the grease compositions containing the metallo compounds as compared to the poorer stability of ordinary grease compositions not containing such metallo compounds.

EXAMPLE .IV

' Improved ggg z Precision Grease Makeup: Per Cent by Weight:

200 M. 0. Neutral Oil 81. 6 81.1 150 M. 0. Oil 7.1 7. 1 Sodium Soap of Tal]ow 7.0 7. 0 Sodium Soap of Stearic Acid. 3. 5 3. 5 Glycerine (Theoretical) 0. 7 0. 7 Added Excess Compounding Alkali as a H 0.1 0. 1 Compound of Example I 0. 5 Inspection:

Gravity, API 22. 0 22. e Melting Point, F., Hawxhurst 263 263 Dropping Point, F., ASTM D 566-42---- 344 344 Flow Point, F., Navy Dept. Spec.

14-G-1d 245 246 Penetration, ASIM D 217-381", 77 F., 150 G., 5 Sec:

Unworked '312 314 Worked 325 328 Oxygen Stability, 176 F., Hr., Method 272, Gulf 1 100 500+ Bleeding Test, Per Cent, AN-G-3a Mod, 150 F., 50 Hr., Separated Oil, Per Cent by Weight 7 1 l Method 272 Gulf, is a modification of ASTM D 942-47T. In the modification, instead of measuring the pressure drop after 100 hours,

50 the time required to give a 10 pound pressure drop is measured.-

EXAMPLE V Cup Imgroved D Grease Grease Make-up: Per Cent by Weight: 300 Vis. Texas Oil 83. 2 82. 7 Calcium Soap of Ta1low 14. 4 14. 4 Glycerine (Theoretical) 1.4 1. 4 Water 1. 0 1. 0 Compound of Example I 0. 5 60 Inspection:

Gravity, API 18.5 18. s Melting Point, F., Hawxhursus 189 190 Flow Point, E. Navy Dept. Spec. 1 i G;-

lri 207 207 Consistency: mIn., Braun, 77 F., 2.50 G 30 30 Penetration, ASTM D 217 38T, 77 F., 150 G., 5 Sec.:

Unworked 230 232'. Worked 280 282 Oxygen Stab ty, 176 F., Hr., Method 272, Gulf 50 500+ Bleeding Test, Per Cent, AN-G-3a' Mod, 150 F., 50 Hr., Separated Oil, Per Cent by Weight 6. 5 .0. 5

Chassis 8523;? Lubri- Lubri; cant cant Make-up: Per Cent by Weight:

- 100/2 Parafline Oil i5. 7 15. 500/3 Texas Oil." 4. 4. 1900/50 Texas OiL- 33. 2 33. 150 M. 0. Oil 37.1 36. Sodium Soup of Tallow 5. 8 5. Calcium Soap of Tallow--. 2. 3 2. Glycerine (Theoretical) 0, 8 0, Added Excess Compounding Alkali as NaOE 0.1 0. Sulfurized Lard 0il 1.0 1. Compound of Example I- 0.

Inspection:

Gravity, API 21. 21'. Dropping Point, F,. ASIM D 5616-42.". 258 25 Flow Point, F., Navy Dept. Spec. l4-G id 150 150 Consistency, mun: Braun, 77 F., 2.50 G- 1? '17 Penetration, ASTM D 217-471: 32 F.,

150 G., 5 Sec.:

Unworked '303 303 Worked 375 375 77 F., 150 G., 5 Sec.-

Unworked. 363 363 Worked 380 380 Convis Test, Furol, Se

32 F., 5,200 Grams l 498 498 77 F.,.l,200 Grams I 15 i 1 Oxygen Stability, 176 F., Hr., Method 272, Gulf 45 500+ Bleeding Test, Per Cent, ANG3a Mod.

150 F., 50 Hr. Separated Oil, Per Cent by Weight l2 2 0n freshly prepared sample before aging.

and a small amount of the reaction product prepared by reacting an aqueous slurry of 1 mol of a metal hydroxide selected from the group consisting of barium, strontium, magnesium and calcium hydroxides with from 2 to 4 mols of 1 formaldehyde at a mildly elevated temperature and condensing the resulting product with from 0.5 to 1 mol of aniline and from 2 to 4 mols of a mono-alkyl phenol having from 4 to 12 carbon atoms in the allryl substituent, said product be- .ingpresent in an amount sufficient. tov stabilize 'the grease against oxidative deterioration.

2.- A'grease composition comprising a mineral lubricating oil thickened to a grease by a soap, "and a small'amount of the reaction product prepared by. reacting an aqueous slurry of 1 mol ofia metal hydroxide selected from the group consistingof barium, strontium, magnesium and calcium hydroxides with from 2 to -4-- mols of .formaldehyde at a temperature not exceeding 200 F. and condensing the resulting product with from 0.5 to 1 mol of aniline and from 2 to 4 mols of a mono-alkyl phenol having from 4 to 12 carbon atoms in the alkyl substituent, said prodnot being present in an amount sufiicient to stabilize the grease against oxidative deterioration.

'3. The composition of claim 2, wherein the said reaction product is present in an amount of from 0.1 to 5.0 per cent by weight on the grease.

4. A grease composition comprising a mineral lubricating oil thickened to a grease by a soap, and a small amount of the reaction product preparedbyxeactingan. aqueous slurryof .1. mol .Q

8 a. metal-hydroxide selected from the group consisti-ng ofbarium, strontium, magnesium and calcium hydroxides with from 2 to 4 mols of formaldehyde-at a temperature not exceeding 200 F.

and condensing the resulting product at a temperature not exceeding 200 F. with from 0.5 to 1 mol of aniline and from 2 to 4 mols of a monoalkyl phenol having from 4 to 12 carbon atoms in the alkyl substituent, said reaction product being present in an amount sufficient to stabilize the grease against oxidative deterioration.

5. A grease composition comprising a mineral lubricating oil thickened to a grease by a soap, and a small amount of the reaction product prepared by reacting an aqueous slurry of 1 mol of calcium hydroxide with about 3 mole of formaldehyde at a temperature of about 160 F., and condensing the resulting product with about 0.7 mol of. aniline and 2.3 mols of para tetramethylbutyl phenol at a temperature not exceeding 200 F., said reaction product being present in an amount sufficient to stabilize the grease against oxidative deterioration.

6. A semi-fluid oil suitable for the lubrication of light mechanisms comprising a mineral lubrieating oil thickened to a semi-fluid oil by a soap, and a small amount of the reaction product prepared by reacting an aqueous slurry of 1 mol of a metal hydroxide selected from the group consisting of barium, strontium, magnesium and calcium hydroxide with from 2 to 4 mols of formaldehyde at a temperature not exceeding :200" FI and condensing the resulting product at a temperature not exceeding 200 F. with from uct beingpresent in an amount-sufiicient to stabilize the semi-fluid oil against oxidative deterioration.

7. A semi-fluid oil suitable for the lubrication of light mechanisms comprising a mineral lubricating oil thickened to a semi-fluid oil by the calcium soap of tallow, and a small amount of the reaction product prepared by reacting an aqueous slurry of 1 mol of calcium hydroxide with about 3 mols of formaldehyde at a temperature of about 160 F. and condensing the resulting product with about 0.7 mol of aniline and 2.3 mols of para tetramethylbutyl phenol at a temperature not exceeding 200 F., said reaction product being present in an amount sufiicient to stabilizethe semi-fluid oil against oxidative" deterioration;

8. Thesemi-fiuid oil of claim '7, wherein the said reaction product is present in an, amount of from 0.1 to 5.0 per cent by weight on the semifluid 0i1.,

9.; A semi-fluid oil suitable for the lubrication of lightimechanisms comprising at soft grease having-the following-approximate composition in parts by weight: 1

Mineral lubricating oil, 300 s. U. s. at

F 91.3 Calcium soap of tallow 6.9 YCe Water "L 0.6

mol. of. aniline and; 2.3 mole of Para tetramethyl butyl phenol at a temperature. not exoeeding HERSCHEL G. SMITH. TROY L. CANTRELL,

REFERENCES CITED The following references are of record, in the file of this patent:

UNITED STATES PATENTS Number Name Date Beerbower et a1. July 14, 1942 Number Name Date Zimmer et a1. Jan. 25, 1944 Oberright July 11, 1944 McCleary Nov. 21, 1944 Griflin et a1; Nov. 5, 1946 McCleary Apr. 27, 1948 Calvert et a1 Sept. 21, 1948 McNab et a1 Oct. 12, 1948 

1. A GREASE COMPOSITION COMPRISING A MINERAL LUBRICATING OIL THICKENED TO A GREASE BY A SOAP, AND A SMALL AMOUNT OF THE REACTION PRODUCT PREPARED BY REACTING AN AQUEOUS SLURRY OF 1 MOLE OF A METAL HYDROXIDE SELECTED FROM THE GROUP CONSISTING OF BARIUM, STRONTIUM, MAGNESIUM AND CALCIUM HYDROXIDES WITH FROM 2 TO 4 MOLS OF FORMALDEHYDE AT A MILDY ELEVATED TEMPERATURE AND CONDENSING THE RESULTING PRODUCT WITH FROM 0.5 TO 1 MOLE OF ANILINE AND FROM 2 TO 4 MOLS OF A MONO-ALKYL PHENOL HAVING FROM 4 TO12 CARBON ATOMS IN THE ALKYL SUBSTITUENT, SAID PRODUCT BEING PRESENT IN AN AMOUNT SUFFICIENT TO STABILIZE THE GREASE AGAINST OXIDATIVE DETERIORATION. 